![]() However, querying on the original object will also access that object: SELECT * FROM sales.product A query such as this will look for the local object first (which does not exist), and then the synonym: SELECT * FROM product Notice that both objects have the same name. All users can query the cust synonym and access the sales.customers table (if they have access to the underlying sales.customers table).Įxample 3 – Same name CREATE SYNONYM product This will create a new public synonym for the customer object in the sales schema. This creates a new private synonym called emp, which refers to the employees object in the hr schema.Įxample 2 – Create public synonym CREATE PUBLIC SYNONYM cust Example 1 – Create private synonym CREATE SYNONYM emp Let’s see some examples of creating a synonym. dblink_name: This is the name of the database link if it is required.Ī synonym can be created on the following types of objects:.object_name: The name of the object that the synonym will relate to.FOR schema: The schema is optional, but specifies the schema name that the object exists in.I say should, because names longer than 30 characters can be created and dropped, but they are transformed into a shorter string for storage. synonym_name: The name of the new synonym that is being created.If you are creating a PUBLIC synonym, you cannot specify a schema. If this is omitted, the synonym is created in your own schema. schema: This is optional and is the name of the schema you want to create the synonym in.If this is omitted, a private synonym is created. PUBLIC: Use the PUBLIC keyword to create a public synonym.OR REPLACE: This is optional and allows you to replace an existing synonym name, instead of dropping it and recreating it.The syntax is: CREATE SYNONYM synonym_nameįOR object_name parameters for this function are: To create a synonym in Oracle (either private or public), we use the CREATE SYNONYM command. Sure, they can make management a bit easier, but they can pose a security risk and can make development harder, because there’s an object that exists and available to all users. Generally, it’s a good idea to avoid creating public synonyms. Third, after schema objects and private synonyms This is how public synonyms and private synonyms compare: Criteria ![]() If a private synonym is not found, Oracle will look in the public synonyms. If a schema object is not found, Oracle will look in the private synonyms for the user. Oracle will look at the user’s schema for the object name. The order of precedence for objects and synonyms is: Just like how, in mathematics, the multiplication and division are performed before the addition and subtraction, Oracle has an order in the way that the objects are looked up. This is a valid scenario, and Oracle has rules on which order they are processed in. What happens if you have a public synonym with the same name as an existing object? Or a private synonym? The synonym name must be unique within the schema.
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